Custom calling features are well-known for telephone systems. With the advent of electronic components and especially integrated circuits, the providing of these service features may be accomplished expediently in an inexpensive manner. These features may be provided both in the computercontrolled exchanges now being developed and produced in the electromechanical exchanges prevalent in the industry.
Such special features are shown, for example in U.S. Pat. No. 3,377,433 issued 4/9/68 to W. Whiteney, U.S. Pat. No. 3,342,934 issued 9/19/67 to H. Koh et al, and U.S. Pat. No. 3,811,015 of 5/14/74 to R. Beth et al.